Reticulated grating

ABSTRACT

An improved reticulated grating comprising an apertured sheet and serrations projecting from the aperture edges of at least one of the surfaces of the sheet, each of the serrations of each aperture being skewed with respect to the next adjacent serration, to increase frictional resistance.

' United States Patent Balinski et a1.

[ Dec. 16, 1975 1 1 RETICULATED GRATING 2.828.843 4/1958 Hill 52/180 '7 W51 Henry Bali-ski, Hoffman E8868 $232??? 21133? 2iil..iiijiijjiiiiiiiii1111;111:1111: 251138 Albert R n Elk Grove Village, 3,752,396 8/1973 Bustin 52/660 both of 111.

[73] Asslgnee: S Gypsum Company Primary Examiner.l ohn E. Murtagh Attorney, Agent, or Flrm-Samuel Kurlandsky, Esq.; [22] Filed: Nov. 16, 1973 Kenneth E. Roberts, Esq.; Stanton T. Hadley, Esq.

[21] Appl. No.1 416,481

57 ABSTRACT [52] US. Cl. 52/180 1 [51] It'll. C1.2 E04C 2/42; E041: 11/16 An improved reticulated grating comprising an aper [58] Fleld of Search 52/177, 660, 180, 670, tured Sheet and serrations projecting from the aper 52/666r 672; 404/1941; 15/215 ture edges of at least one of the surfaces of the sheet, 238-240; 238/14; 119/9 28 each of the serrations of each aperture being skewed with respect to the next adjacent serration, to increase [56] References C'ted frictional resistance.

UNITED STATES PATENTS 2360,416 8/1956 Bates .7 52/180 9 Claims, 6 Drawing Figures US. Patent Dec. 16, 1975 SheetlofZ 3,925,946

US. Patent Dec. 16, 1975 Sheet 2 of2 3,925,946

Fig.6

Fig. 5

RETICULATEI) GRATING BACKGROUND OF THE INVENTION Platforms, walkways, stair treads, and walk-on gratings of all kinds commonly are reticulated or otherwise perforated to provide enhanced strength, openings for visibility and water run-off, and greater friction. Some of these provide the perforations in the form of spaced apart circular or oblong-shaped apertures, which may or may not be in rows. Friction is reduced by upsetting or otherwise forming the edges of the apertures so that they are given side walls the depth of which exceeds the original sheet dimension. The edge portion of the side wall which is walked upon thus provides an anti-slip projection rising above the surface of the sheet generally forming the grating. An example of such construction is shown in US. Pat. No. 3,181,440.

A more sophisticated construction is the reticulated grating shown in U.S. Pat. No. 2,828,843, wherein the apertures are formed in rows, alternate rows being longitudinally offset with respect to the longitudinal axis of the grating, the aperture side walls being bent so as to form a diamond shape. Apertures in each row are joined by a saddle, the saddles in adjacent rows being located on or adjacent to opposite surfaces of the sheet, thus creating a beam-like structure for enhanced strength. The edge portions of the side walls projecting above at least one of the surfaces of the sheet are provided with serrations or projections which tend to grip whatever is passed over the grating, thus reducing the slippage thereover. This construction has been found to provide, among other things, superior frictional resistance over the supporting surface, except in the transverse direction of the grating. It is this direction that the rows of apertures, and therefore the side walls of the apertures, generally extend. As the serrations are retained in the plane of the side walls, they give maximum slip resistance only in the perpendicular, or longitudinal, direction.

The instant invention is an improvement over the foredescribed reticulated grating, to achieve greater frictional resistance.

SUMMARY OF THE INVENTION The invention relates to a reticulated grating characterized by improved resistance to slippage, or increased frictional resistance, at the surface over which people or objects are transported. More specifically, there is provided an improved grating including a sheet having opposite surfaces and apertures therein, the apertures being defined by side walls having opposite edge portions which are spaced apart by a distance greater than the thickness of the sheet, the side wall edge portions projecting from at least one of the sheet surfaces being provided with serrations thereon to reduce slippage over the sheet; the improvement wherein each of the serrations is skewed with respect to the next adjacent serration of that edge portion whereby slippage over the sheet is further reduced.

Accordingly, it is an object of the invention to provide a reticulated grating having opposite surfaces, at least one of the surfaces being provided with means giving increased frictional resistance to objects slid thereover, regardless of the direction of movement.

It is a related object of the invention to provide such a grating in an inexpensive manner, using a minimum of additional processing.

Other objects and advantages will become apparent upon reference to the following description of the drawings and of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary plan view of the improved grating constructed in accordance with the invention;

FIG. 2 is a sectional view taken generally along the line IIII of FIG. 1; 0

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is described hereinafter as it relates to a certain kind of reticulated grating. However, it is not so limited. It will be appreciated that it can be applied also to any grating, usually for carrying loads, having apertures the edge portions of which are serrated for frictional resistance.

Turning now to FIG. 1, there is illustrated a reticulated grating generally of the type shown in the aforesaid U.S. Pat. No. 2,828,843. That is, the grating 10 comprises an elongate sheet having opposite surfaces or faces 12 and 14, and opposite side margins 16 defining the limits of the transverse axis of the grating. Alternate rows 20 and 20 of apertures 22 are repeatedly formed in the sheet along its longitudinal axis, leaving the side margins unperforated so as to form side flanges which may be bent, as shown in phantom, FIG. 2. The surface 12 thus becomes the top surface over which loads are transported. Each of the apertures is defined by a side wall 24 (FIG. 2) which extends transversely across the plane of the sheet and terminates in opposite edge portions 26 and 28. A bridge or saddle 30, 30 joins each aperture to the next adjacent aperture of the rows 20, 20', respectively. The saddle of each row joins the next adjacent row at the general midpoint of an aperture therein. The saddles 30 generally lie in one plane, while saddles 30' are in another plane spaced from the plane of saddles 30. Thus, the surface of the sheet to which each saddle is adjacent alternates from row to row, thereby forming the row of apertures into a beam-like structure for greater strength. As shown in FIG. 2, only the edge portion 26 need be provided with projections or serrations 40. Alternatively, however, edge portion 28 may have such serrations, shown in phantom, FIG. 2, albeit transversely spaced from those of portion 26. As shown in FIG. I, the apertures 22 are thus formed into diamond shapes, the apertures of one row being longitudinallyoffset with respect to the apertures of the next adjacent row.

In accordance with one aspect of the invention, the serrations 40 of each aperture are bent so as to give increased frictional resistance. More specifically, referring to FIG. 3 in particular, one side of the diamond has an odd number of serrations, 41 through 45, while the opposite side has an even number, 46 through 49. This is due to the fact that the serrations of each aperture side are initially punched as mating pairs, as described in the aforesaid US. Pat. No. 2,828,843. Although the total number of serrations for any aperture, projecting from one surface, is shown to be nine, any odd number may, of course, be used.

The serrations are positioned in the final product so that each one is skewed with respect to the next adjacent one for that aperture, projecting from that surface of the sheet. As shown in FIG. 3, this may be achieved by twisting serrations 41, 43, 45, 47 and 49 with respect to the plane of edge portion 26 of the aperture, through an angle alpha. The other serrations remain in the plane of the edge portion. Preferably, alpha equals between about lO and about 15. The result is that no longer do the serrations tend to line up in the transverse direction, but rather they extend in several directions, increasing frictional resistance over surface 12 of the sheet.

FIGS. 4-6 illustrate several alternate embodiments of the invention, wherein the serrations are twisted differently from that shown in FIGS. l-3. Parts similar to those previously described bear the same reference numeral to which the distinguishing suffixes a through c, respectively, have been added.

Thus, FIG. 4 illustrates a serrated aperture 22a identical to that shown in FIG. 3, except that serrations 42a, and 44a, rather than 41a, 43a, and 45a, have been twisted out of the plane of the edge portion 26a, through angle alpha. Serrations 46a-49a remain twisted, or not twisted, respectively, as in the previous embodiment. The result is to produce serrations less than half of which are skewed with respect to the aperture edge portion from which they project.

In FIG. 5, the same serrations 40b are twisted with respect to the edge portion as in FIG. 4, except that serrations 47b and 49b have been twisted in opposite directions. The result is that diagonally opposite serrations 42b, 49b are generally mutually parallel, as are diagonally opposite serrations 44b, 47b.

FIG. 6 illustrates each and every one of the serrations 410 through 49c being skewed with respect to the edge portion 26c from which they project. As in each of the previous embodiments, the angle through which the serration is twisted is between about and about The manner and apparatus for achieving the aforedescribed configurations is generally that set forth in the aforesaid U.S. Pat. No. 2,828,843, as well as the companion U.S. Pat. No. 2,828,792. The twisting of the serrations out of the plane of the aperture edge portions may be achieved by dies which angularly deflect the appropriate serrations at the time the aperture slits are initially punched. Thus, a minimum of additional processing is required in that the skewing or twisting is achieved during the other processing of the sheet.

Although the invention has been described in connection with certain preferred embodiments, it is not intended that it be limited thereto. Rather it is intended that the invention cover all alternate arrangements, equivalents, and embodiments as may be included within the scope of the following claims.

What is claimed is:

1. In a grating including a sheet having opposite surfaces and apertures therein, said apertures being defined by side walls, each said side wall extending transversely across the sheet to opposite edge portion which are spaced apart by a distance greater than the thickness of said sheet, the side wall edge portions projecting from at least one of said sheet surfaces being provided with serrations thereon to reduce slippage over the sheet;

the improvement wherein at least alternate serrations are each twisted through an angle with respect to the plane of the edge portion of the aperture, the resulting structure being so arranged that each of said serrations is skewed with respect to the next adjacent serration of that edge portion whereby slippage over the sheet is further reduced.

2. The improved grating as defined in claim 1, wherein less than one half of said serrations projecting from one of said surfaces is skewed with respect to said edge portion from which they project.

3. The improved grating as defined in claim 2, wherein said apertures are diamond shaped.

4. The improved grating as defined in claim 3, wherein for at least one of said surfaces, each of said skewed serrations is generally parallel to the skewed serration diagonally opposite to it in that aperture.

5. The improved grating as defined in claim 1, wherein said grating has a longitudinal axis and a transverse axis, the apertures are in rows, and wherein the apertures of each row are longitudinally offset with respect to the apertures of the next adjacent row.

6. The improved grating as defined in claim 5, wherein the adjacent apertures of each row are joined by a saddle, said saddle of each row being located generally in a single plane, the planes of said saddles of adjacent rows being spaced apart.

7. The improved grating as defined in claim 1, wherein said apertures are diamond shaped.

8. The improved grating as defined in claim 1, wherein the apertures are in rows and the adjacent apertures of each row are joined by a saddle, said saddle of each row being located generally in a single plane, the planes of said saddles of adjacent rows being spaced apart.

9. In a grating including a sheet having opposite surfaces and apertures therein, said apertures being defined by side walls, each said side wall extending transversely across the sheet to opposite edge portions which-are spaced apart by a distance greater than the thickness of said sheet, the side wall edge portions projecting from at least one of said sheet surfaces being provided with serrations thereon to reduce slippage over the sheet;

the improvement wherein at least alternate serrations are each twisted through an angle with respect to the plane of the edge portion of the aperture, the resulting structure being so arranged that each of said serrations is skewed with respect to said aperture edge from which it projects whereby slippage over the sheet is further reduced. 

1. In a grating including a sheet having opposite surfaces and apertures therein, said apertures being defined by side walls, each said side wall extending transversely across the sheet to opposite edge portion which are spaced apart by a distance greater than the thickness of said sheet, the side wall edge portions projecting from at least one of said sheet surfaces being provided with serrations thereon to reduce slippage over the sheet; the improvement wherein at least alternate serrations are each twisted through an angle with respect to the plane of the edge portion of the aperture, the resulting structure being so arranged that each of said serrations is skewed with respect to the next adjacent serration of that edge portion whereby slippage over the sheet is further reduced.
 2. The improved grating as defined in claim 1, wherein less than one half of said serrations projecting from one of said surfaces is skewed with respect to said edge portion from which they project.
 3. The improved grating as defined in claim 2, wherein said apertures are diamond shaped.
 4. The improved grating as defined in claim 3, wherein for at least one of said surfaces, each of said skewed serrations is generally parallel to the skewed serration diagonally opposite to it in that aperture.
 5. The improved grating as defined in claim 1, wherein said grating has a longitudinal axis and a transverse axis, the apertures are in rows, and wherein the apertures of each row are longitudinally offset with respect to the apertures of the next adjacent row.
 6. The improved grating as defined in claim 5, wherein the adjacent apertures of each row are joined by a saddle, said saddle of each row being located generally in a single plane, the planes of said saddles of adjacent rows being spaced apart.
 7. The improved grating as defined in claim 1, wherein said apertures are diamond shaped.
 8. The improved grating as defined in claim 1, wherein the apertures are in rows and the adjacent apertures of each row are joined by a saddle, said saddle of each row being located generally in a single plane, the planes of said saddles of adjacent rows being spaced apart.
 9. In a grating including a sheet having opposite surfaces and apertures therein, said apertures being defined by side walls, each said side wall extending transversely across the sheet to opposite edge portions which are spaced apart by a distance greater than the thickness of said sheet, the side wall edge portions projecting from at least one of said sheet surfaces being provided with serrations thereon to reduce slippage over the sheet; the improvement wherein at least alternate serrations are each twisted through an angle with respect to the plane of the edge portion of the aperture, the resulting structure being so arranged that each of said serrations is skewed with respect to said aperture edge from which it projects whereby slippage over the sheet is further reduced. 